M4 Turbohead Paradox

brightnorm

Flashaholic
Joined
Oct 13, 2001
Messages
7,160
In this past thread I described the excellent performance of the SF 2.5" SRTH turbohead as presented by LPS


NEW TURBO: A MAJOR STEP FORWARD



I obtained three of them to add to my two existing 3" T1/2's (The 1 and 2 are identical, but differently designated according to the installed lamp, a confusing practice IMO, so I just call them T1/2, or perhaps T1-2 might be clearer).

I found that a D3 with N2 lamp in the T1/2 gave performance equal to the UltraStinger, while the SRTH came very close to the same standard. This was remarkable considering the small size and light weight of the combined unit.

Today, with this in mind I added an A19 extender to my D3, loaded one of the T1/2's with an MN60 and prepared for spectacular results, but was disappointed with the oblong, somewhat sloppy, subtly shadowed beam. I could live with the shape but not with the shadowing. I tried repositioning the lamp with a washer which just made it worse. I also tried a MN61 and was not impressed. That is one heck of a load for only 4 123's and the beam was actually slightly dimmer than my MN60 in addition to retaining the oblong shape and shadows. I went back to the MN60 and tried my second T1/2: similar result. I went through all my SRTH's: slightly better but still subpar and not nearly as round and perfectly focused as the D3 + N2.

I know that any Flashaholic can understand my surprise and frustration; I have a vague memory of someone posting something similar, but I don't remember the particulars.

Perhaps it is my particular MN60. It's my only one and I am not enthusiastic about ordering another one for the sake of comparison.

I have a few questions:

Is the M4's turbohead identical to either the SRTH or T1/2? If it is then I'll assume that the oblong imperfect beam is intrinsic to the M4 and must be accepted.

If it's different and creates a superior beam is there any way to buy it as an add-on to my present set up, or are the tube diameters different? (I seem to recall that they are). I think one of our LEO's got an M4 some time ago and was very pleased with it. If it's different but excellent then I'll just bite the bullet and get an M4, though I would prefer saving that money toward the A2.

Any input and suggestions will be much appreciated.

Brightnorm
 

Sean

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My M4 with/MN60 was very oval, but looked much worse (more squashed) when I put the same MN60 in my SRTH T-Head. It seems that the KT-4 T-Head on the M4 does a better job of scattering the light to make the oval beam look less oval & more acceptable. I actually like the MN60 in the M4, it is pretty oval, but it is also pretty bright/tight hotspot. I didn't like the MN61 in the M4 at all, the hotspot was too wide, slightly yellow even with fresh batteries, not as much throw as the MN60. The only good thing about the MN61 was that the beam was much more circular than than the oval MN60. The MN61 might look better in the SRTH, I no longer have one to try it like you did, although it sounds like you didn't care for it either.

The only 4-cell LA that looks great is the N62, nice and round & bright. the problem with it though is that it only stays bright for a few minutes.

If you decide to sell either your MN60 or MN61 let me know.
wink.gif
 

Size15's

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Kettering, England
I have to compose my comments.

And perhaps try about a few option only today made available to me.

I currently have two M4's with MN61's that I'm very pleased with. I also have a 12PM with 3" TurboHead (12PMT) with MN61 that I'm extremely impressed with.

Now I may only have a limited number of TurboHeads and lamps, but for me, the MN60, like the MN10 and the MN15 just aren't round or white/bright enough.

Jahn and I will be meeting up soon to do a TurboHead review so I have a second pair of hands and a second opinion on the kit I have.

Agreed the N62 produces the nicest beam in practically all my TurboHeads, but it's runtime is a real drag.

I have to say that I'm scared that if I do this review I will use up my reserves of SF123As. I need to secure my next shipment from The Prince ASAP!

Today he sent through two additional T TurboHeads so I now have three plus the T3.

I will use the #numbers that PK used in this photo:

#1 ("T" 3" TurboHead)
#2 ("12PM" 2.5" TurboHead)
#3 ("SRTH" 2.5" TurboHead)
#4 ("KT" 2.5" Pyrex TurboHead)
#5 ("Millennium TurboHead, 2.5" Pyrex)

What I've got:

#1 (x3)
#2 (x1)
#3 (x1)
#4 (x2)
#5 (x6)

T3 (x1)
KT3 (x1)

I also have five Lexan version of #5 (4 ruined).

TurboHead Lamps:

N1 (x1)
N2 (x3)
N3 (x2)
N4 (x2)
N5 (x1)

MN15 (x4)
MN16 (x5)

MN20 (x4)
MN21 (x3)

MN60 (x1)
MN61 (x4)
N62 (x2)

That's 15 TurboHeads and 32 Lamps.

It's a start I know, and I hope to get a more representative sample over the next few months.

Thinking about 4 cell bodies...
I can run Four #5's, and two Standard bodies with TurboHeads (#1 - #4)

Jahn and I have our work cut out.

If you have any idea of a testing method, or specific combinations you would like me to compare, please let me know.

Thanks

Al
 

brightnorm

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Joined
Oct 13, 2001
Messages
7,160
Originally posted by Size15s:
....Jahn and I have our work cut out...
If you have any idea of a testing method, or specific combinations you would like me to compare, please let me know....
<font size="2" face="Verdana, Arial">AL,

That is one s**t load of turboheads! I can't imagine that I would devise any testing methodology superior to what you and Jahn will create. That will be an extraordinary (and much needed) review.

That's 15 TurboHeads and 32 Lamps.
It's a start I know, and I hope to get a more representative sample over the next few months.


Al, if that's a start I can't even begin to imagine what the finish might be! I'm really excited about this upcoming review because this is something never done before on CPF (as far as I can remember): a thorough review of an entire category of SF equipment, performed by two highly knowledgeable and experienced members.

Getting back to my specific situation: Al, you are quite pleased with the MN61 in both the M4 and the 12PM and Sean, you seem quite happy with the MN60 in the M4. I believe the different observations are probably a function of the apparently unavoidable differences from one T-head or lamp to the next.. This only adds to the frustration. It's beginning to look like I may "have to" get an M4. Oh well, I'm reconciled to it..... (might one call that a happy reconciliation?)

Brightnorm
 
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